Banning, California (CNN) -- How could a man who allegedly had explosives hidden in his underwear have been allowed to board a plane headed for the United States?

Anti-terrorism experts say it never should have happened, and that specially trained bomb-sniffing dogs could have provided a low-tech way to detect such items.

"The fact that this individual showed up with a one-way ticket, purchased with cash and no checked baggage -- he should have been pulled aside," said security expert Larry Berg, a consultant with Berg Associates. "And at that point, if inspected by a dog, he literally could have been detected."

Umar Farouk AbdulMutallab, the man accused of trying to blow up a U.S. airliner bound for Detroit, Michigan, had a one-way ticket from Accra, Ghana, to Lagos, Nigeria, and a round-trip ticket for his trip from Lagos to the Netherlands and then to Detroit, according to the Nigerian Aviation Authority.

About 700 bomb-sniffing dogs currently work at U.S. airports. They are trained to detect up to a dozen different explosive compounds, including PETN, the compound that AbdulMutallab is alleged to have smuggled aboard Northwest flight 253 to Detroit on December 25.

The dogs used by the Transportation Security Administration are trained at Lackland Air Force Base near San Antonio, Texas. They patrol airport terminals, check unidentified packages and sniff baggage that raise alarms during X-ray screening. The dogs are not currently used specifically to sniff out explosives on people. But they could be, according to trainer Patrick Beltz.

"A well-trained dog and a very good, well-trained handler can find explosives with little or no false alarms," Beltz said. "And if they had been doing it, it might have deterred him from trying to get on the plane in the first place."

Beltz trains explosive-sniffing dogs on a 10-acre ranch near Banning, California. The dogs have been used by law enforcement personnel across the country and overseas.

Beltz and some of the handlers he is training alongside the dogs demonstrated for CNN how the dogs work.

In a series of exercises, a German shepherd named Bear quickly located a variety of explosives planted beneath cars, around a simulated town square, and in an old school bus, which Beltz says makes a good substitute for the interior of an airplane.

Bear and his handler William Yocham work for the Los Angeles Port Authority Police in California.

Since the September 11, 2001, terror attacks against the United States, Bear has been used to search for explosives on cruise ships, baggage and cargo entering and leaving the Los Angeles Harbor. The cost of Bear's training over the years adds up to $60,000.

Beltz does not train most dogs to search people.

"In America, it could be considered very intrusive to make you stand still while my dog went to your groin area and smelled it," Beltz said.

But, Beltz said, the dogs he trains for overseas duty are sometimes trained for personnel searches.

At Auburn University in Alabama, researchers are working on less intrusive ways for dogs to detect explosives carried by people. The school is in the process of patenting a process in which dogs would sample the air left in the wake of travelers passing through an airport terminal.

The Auburn trainers believe their dogs can detect very small traces of explosives and then follow the trail to the person carrying a bomb.

Fran Townsend, a former homeland security adviser to President George W. Bush and a current CNN contributor on national security issues, says the use of dogs in airports should be expanded.

"Dogs tend to be the cheapest, fastest and most reliable explosive detection capacity that we have in this country," Townsend said.